Ims service leasing

ABSTRACT

Embodiments of a method performed by an Interconnect Border Control Function (IBCF) in an Internet Protocol (IP) Multimedia Subsystem (IMS) network and corresponding embodiments of an IBCF are disclosed. In some embodiments, the method performed by the IBCF comprises receiving, from an IMS node in a virtual IMS network domain of a virtual IMS network operator, a Session Initiation Protocol (SIP) message that serves as a request for a leased IMS service. The SIP message comprises information that identifies the leased IMS service, information that identifies an IMS network slice, information that identifies the virtual IMS network operator, information that identifies one or more sub-services requested for the leased IMS service, and/or information that identifies an IMS network slice instance. The method further comprises making a decision as to whether to accept or reject the request based on the information comprised in the SIP message.

RELATED APPLICATIONS

This application claims the benefit of provisional patent applicationserial number 62/751,276, filed Oct. 26, 2018, the disclosure of whichis hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to an Internet Protocol (IP) MultimediaSubsystem (IMS) and, in particular, IMS services as they relate toMobile Virtual Network Operators (MVNOs).

BACKGROUND

The Internet Protocol (IP) Multimedia Subsystem (IMS) is used to providemany types of services in relation to a cellular communications system.There is a need for IMS service solutions that provide flexibility tonetwork operators.

SUMMARY

Systems and methods are disclosed herein that enable Internet Protocol(IP) Multimedia Subsystem (IMS) service leasing. Embodiments of a methodperformed by an Interconnect Border Control Function (IBCF) in an IMSnetwork and corresponding embodiments of an IBCF are disclosed. In someembodiments, a method performed by an IBCF in an IMS network of an IMSservice provider to provide IMS services to a virtual IMS networkoperator comprises receiving, from an IMS node in a virtual IMS networkdomain of a virtual IMS network operator, a Session Initiation Protocol(SIP) message that serves as a request for a leased IMS service. The SIPmessage comprises information that identifies the leased IMS service,information that identifies an IMS network slice, information thatidentifies the virtual IMS network operator, information that identifiesone or more sub-services requested for the leased IMS service,information that identifies an IMS network slice instance, or anycombination thereof.

The method further comprises making a decision as to whether to acceptthe request for the leased IMS service or reject the request for theleased IMS service based on the information comprised in the SIPmessage.

In some embodiments, the SIP message comprises information thatidentifies an IMS network slice, where the IMS network slice isassociated with the leased IMS service. In some other embodiments, theSIP message comprises information that identifies an IMS network sliceinstance, where the IMS network slice instance is an instance of an IMSnetwork slice associated with the leased IMS service.

In some embodiments, the decision is to accept the request for theleased IMS service, and the method further comprises, upon making thedecision to accept the request for the leased IMS service, initiatingthe requested IMS service using one or more IMS nodes in the IMSnetwork. In some embodiments, the method further comprises creating oneor more charging data records that reflect that the requested leased IMSservice was provided for the virtual IMS network operator.

In some embodiments, the decision is to reject the request for theleased IMS service, and the method further comprises, upon making thedecision to reject the request for the leased IMS service, sending amessage to the IMS node in the virtual IMS operator domain thatindicates that the request for the requested leased IMS service isrejected.

In some embodiments, making the decision as to whether to accept therequest for the leased IMS service or reject the request for the leasedIMS service comprises authenticating that the request belongs to thevirtual IMS network operator, ensuring that the virtual IMS networkoperator is entitled for the leased IMS service, validating the IMSnetwork slice and the leased IMS service (e.g., validating that theleased IMS service is one that is leased by the virtual IMS networkoperator), validating that a Session Description Protocol (SDP) matchesthe requested IMS service, or any combination thereof.

In some embodiments, the method further comprises providing at least aportion of the information comprised the SIP message to another IMS nodein the IMS network of the IMS service provider.

In some embodiments, the leased IMS service is a media related function.In some other embodiments, the leased IMS service is transcoding. Insome other embodiments, the leased IMS service is an IMS service relatedto a conference call.

In some embodiments, an IBCF for an IMS network for providing IMSservices to a virtual IMS network operator is adapted to receive, froman IMS node in a virtual IMS network domain of a virtual IMS networkoperator, a SIP message that serves as a request for a leased IMSservice. The SIP message comprises information that identifies theleased IMS service, information that identifies an IMS network slice,information that identifies the virtual IMS network operator,information that identifies one or more sub-services requested for theleased IMS service, information that identifies an IMS network sliceinstance, or any combination thereof. The IBCF is further adapted tomake a decision as to whether to accept the request for the leased IMSservice or reject the request for the leased IMS service based on theinformation comprised in the SIP message.

In some embodiments, a physical IMS infrastructure node that implementsan IBCF for an IMS network for providing leased IMS services to avirtual IMS network operator comprises an interface and processingcircuitry associated with the interface. The processing circuitry isconfigured to cause the physical IMS infrastructure node to implementthe IBCF such that the IBCF operates to receive, from an IMS node in avirtual IMS network domain of a virtual IMS network operator, a SIPmessage that serves as a request for a leased IMS service. The SIPmessage comprises information that identifies the leased IMS service,information that identifies an IMS network slice, information thatidentifies the virtual IMS network operator, information that identifiesone or more sub-services requested for the leased IMS service,information that identifies an IMS network slice instance, or anycombination thereof. The processing circuitry is further configured tocause the physical IMS infrastructure node to implement the IBCF suchthat the IBCF further operates to make a decision as to whether toaccept the request for the leased IMS service or reject the request forthe leased IMS service based on the information comprised in the SIPmessage.

Embodiments of a method performed by an IMS node in a virtual IMSnetwork domain of a virtual IMS network operator to request a leased IMSservice from an IMS network and corresponding embodiments of the IMSnode are also disclosed. In some embodiments, a method performed by anIMS node in a virtual IMS network domain of a virtual IMS networkoperator to request a leased IMS service from an IMS network comprisessending, to an IBCF in the IMS network, a SIP message that serves as arequest for a leased IMS service. The SIP message comprises informationthat identifies the leased IMS service, information that identifies anIMS network slice, information that identifies the virtual IMS networkoperator, information that identifies one or more sub-services requestedfor the leased IMS service, information that identifies an IMS networkslice instance, or any combination thereof.

In some embodiments, the leased IMS service is a media related function.In some other embodiments, the leased IMS service is transcoding. Insome other embodiments, the leased IMS service is an IMS service relatedto a conference call.

In some embodiments, an IMS node in a virtual IMS network domain of avirtual IMS network operator for requesting a leased IMS service from anIMS network is adapted to send, to an IBCF in the IMS network, a SIPmessage that serves as a request for a leased IMS service. The SIPmessage comprises information that identifies the leased IMS service,information that identifies an IMS network slice, information thatidentifies the virtual IMS network operator, information that identifiesone or more sub-services requested for the leased IMS service,information that identifies an IMS network slice instance, or anycombination thereof.

In some embodiments, a physical IMS infrastructure node that implementsan IMS node in a virtual IMS network domain of a virtual IMS networkoperator for requesting a leased IMS service from an IMS networkcomprises an interface and processing circuitry associated with theinterface. The processing circuitry is configured to cause the physicalIMS infrastructure node to implement the IMS node such that the IMS nodeoperates to send, to an IBCF in the IMS network, a SIP message thatserves as a request for a leased IMS service. The SIP message comprisesinformation that identifies the leased IMS service, information thatidentifies an IMS network slice, information that identifies the virtualIMS network operator, information that identifies one or moresub-services requested for the leased IMS service, information thatidentifies an IMS network slice instance, or any combination thereof.

Embodiments of a method performed by an Application Server (AS) in anIMS network of an IMS service provider to provide leased IMS services toa virtual network operator and corresponding embodiments of an AS arealso disclosed. In some embodiments, a method performed by an AS in anIMS network of an IMS service provider to provide leased IMS services toa virtual network operator comprises receiving, from a virtual networkoperator domain of the virtual network operator, a SIP message. Themethod further comprises, upon receiving the SIP message, determiningthat a leased IMS service is needed to process the SIP message andinitiating the leased IMS service in the IMS network of the IMS serviceprovider by sending a second SIP message to another node in the IMSnetwork of the IMS service provider. The second SIP message comprisesinformation that identifies the leased IMS service, information thatidentifies an IMS network slice, information that identifies the virtualnetwork operator, information that identifies one or more sub-servicesdesired for the leased IMS service, information that identifies an IMSnetwork slice instance, or any combination thereof.

In some embodiments, one or more charging data records are created thatreflect that the leased IMS service was provided for the virtual networkoperator.

In some embodiments, the leased IMS service is a media related function.In some other embodiments, the leased IMS service is transcoding. Insome other embodiments, the leased IMS service is an IMS service relatedto a conference call.

In some embodiments, an AS in an IMS network of an IMS service provideris adapted to receive, from a virtual network operator domain of thevirtual network operator, a SIP message. The AS is further adapted to,upon receiving the SIP message, determine that a leased IMS service isneeded to process the SIP message and initiate the leased IMS service inthe IMS network of the IMS service provider by sending a second SIPmessage to another node in the IMS network of the IMS service provider.The second SIP message comprises information that identifies the leasedIMS service, information that identifies an IMS network slice,information that identifies the virtual network operator, informationthat identifies one or more sub-services desired for the leased IMSservice, information that identifies an IMS network slice instance, orany combination thereof.

In some embodiments, a physical IMS infrastructure node that implementsan AS in an IMS network of an IMS service provider comprises aninterface and processing circuitry associated with the interface. Theprocessing circuitry is configured to cause the physical IMSinfrastructure node to implement the AS such that the AS operates toreceive a SIP message from a virtual network operator domain of thevirtual network operator and, upon receiving the SIP message, determinethat a leased IMS service is needed to process the SIP message andinitiate the leased IMS service in the IMS network of the IMS serviceprovider by sending a second SIP message to another node in the IMSnetwork of the IMS service provider. The second SIP message comprisesinformation that identifies the leased IMS service, information thatidentifies an IMS network slice, information that identifies the virtualnetwork operator, information that identifies one or more sub-servicesdesired for the leased IMS service, information that identifies an IMSnetwork slice instance, or any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 illustrates a system in which interaction between an InternetProtocol (IP) Multimedia Subsystem (IMS) node(s) owned by Mobile VirtualNetwork Operators (MVNOs) and an IMS node(s) owned by an IMS serviceprovider is provided in accordance with some embodiments of the presentdisclosure;

FIG. 2 illustrates the operation of an IMS node in a virtual IMSoperator domain and an Interconnect Border Control Function (IBCF) inthe IMS service provider domain in accordance with some embodiments ofthe present disclosure;

FIGS. 3A and 3B illustrate a specific example in which an MVNO owns itsMultimedia Telephony (MMTEL) Application Server (AS) (MTAS) but leasesmedia announcement services from the IMS service provider (e.g., anotherIMS operator) in accordance with an example embodiment of the presentdisclosure;

FIG. 4 illustrates another example embodiment of the present disclosure;

FIG. 5 illustrates an alternative embodiment in which Session Initiation

Protocol (SIP) messages received in the domain of the IMS serviceprovider from the MVNO domain do not include IMS network sliceinformation or other types of information that identifies the requestedleased IMS service(s);

FIG. 6 illustrates the operation of an IMS node in an MVNO domain and anAS in an IMS service provider domain in accordance with one example ofthe alternative embodiment of FIG. 5;

FIG. 7 illustrates the operation of an MVNO domain and an AS in an IMSservice provider domain in accordance with another example of thealternative embodiment of FIG. 5;

FIGS. 8A and 8B illustrate a specific example of the alternativeembodiment of FIG. 5 in which the MVNO is in the IMS service providerdomain and the MVNO leases media announcement services from the IMSservice provider (e.g., another IMS operator);

FIG. 9 is a schematic block diagram of an IMS physical infrastructurenode that implements an IMS entity (e.g., an IMS node, the IBCF, or someother IMS entity) in accordance with some embodiments of the presentdisclosure; and

FIG. 10 is a schematic block diagram of an IMS physical infrastructurenode that implements an IMS entity (e.g., an IMS node, the IBCF, or someother IMS entity) in accordance with some other embodiments of thepresent disclosure.

DETAILED DESCRIPTION

The embodiments set forth below represent information to enable thoseskilled in the art to practice the embodiments and illustrate the bestmode of practicing the embodiments. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the disclosure and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure.

Mobile Virtual Network Operators (MVNOs) offer Voice over Long TermEvolution (VoLTE) and messaging services over Internet Protocol (IP)Multimedia Subsystem (IMS). There are different types of MVNOs. Inparticular, some MVNOs own only IMS nodes and use the Radio AccessNetwork (RAN) and core network of another network operator(s). OtherMVNOs own everything except the RAN. Other types of

MVNOs are between these two extremes.

There currently exist certain challenge(s). Today, the MVNO is eitherfully integrated with some other IMS operator or the MVNO wants to ownthe equipment for the services that the MVNO wants to support.

Internet Protocol (IP) Multimedia Subsystem (IMS) network slicing offersthe advantage of a new business model for Mobile Virtual NetworkOperators (MVNOs) and network operators. Using IMS network slicing, anMVNO can own the IMS control nodes only, and lease other IMS servicesfrom any other IMS operator who can offer these services. These IMSservices can span specific Application Servers (ASs), media resourcessuch as conferencing equipment or announcement, transcoding equipment,etc. IMS network slicing enables leasing of such IMS services. It isalso possible with IMS network slicing to lease some services whileowning other services. So, for example, one MVNO may own its ownMultimedia Telephony (MMTEL) AS (MTAS), while leasing only conferencingequipment, while another may lease everything including the MTAS.

The present disclosure provides solutions in which IMS network slicingenables leasing of IMS services. The present disclosure proposes anexample architecture along with examples that show how this architecturecan work to enable leasing of IMS services.

As discussed in the Background, today, the MVNO is either fullyintegrated with some other IMS operator or the MVNO wants to own theequipment for the services that the MVNO wants to support. Certainaspects of the present disclosure and their embodiments may providesolutions to the aforementioned or other challenges.

Embodiments disclosed herein provide a framework for interaction betweenMVNOs and IMS service providers from whom they are leasing services. Insome embodiments, the interaction between a node (e.g., an IMS node)owned by the MVNO (which is referred to herein as a node in the MVNOdomain or in the “virtual IMS operator domain”) and the IMS serviceprovider goes through a secure Interconnect Border Control Function

(IBCF). In some embodiments, this interaction includes a SessionInitiation Protocol (SIP) message (e.g., a SIP request) that is sentfrom the node in the MVNO domain to the IBCF in the IMS service providerdomain, where the SIP message includes information that identifies anIMS network slice (e.g., an IMS network slice associated with therequested IMS service). The IBCF performs one or more checks to decidewhether to accept the request or reject the request, as will bedescribed below in detail. If the check(s) is(are) successful, therequested service is provided and, in some embodiments, a Charging DataRecord(s) (CDR(s)) is created to capture the information needed foroffline charging settlement.

Certain embodiments may provide one or more of the following technicaladvantage(s). Embodiments disclosed herein propose using IMS networkslicing to enable new business models, leading to higher competition anda more competitive marketplace.

It should be noted that while IMS network slicing is used to identityleased IMS services in many of the embodiments described herein, IMSnetwork slicing is only an example. For instance, when using IMS networkslicing, different IMS network slices may be associated with differentleased IMS services. However, embodiments disclosed herein are notlimited to using IMS network slicing to identify leased IMS services.

Rather, any type of information can be used to identify leased IMSservices and, e.g., included in appropriate messages (e.g., SIPmessages) provided from the MVNO to the IMS network of the IMS serviceprovider and/or within the IMS network of the IMS service provider.

In this regard, FIG. 1 illustrates a system 100 in which interactionbetween an IMS node(s) owned by MVNOs and an IMS node(s) owned by an IMSservice provider is provided in accordance with some embodiments of thepresent disclosure. In this example, there are three MVNOs, but theremay be any number of one or more MVNOs. Each MVNO owns respective IMSnode(s) 102. These IMS node(s) 102 may be IMS control nodes such as,e.g., a Proxy Call Session Control Function(s) (P-CSCF(s)) and ServingCall Session Control Function(s) (S-CSCF(s)) and/or other IMS nodes suchas, e.g., a Home Subscriber Server (HSS) and/or a MTAS. Specifically, inthis example, a first MVNO (MVNO 1) owns one or more IMS nodes 102-1.The IMS nodes 102-1 are referred to herein as being in a “domain” ofMVNO 1. Since we are dealing with the IMS, MVNO 1 is also referred toherein as a virtual IMS operator, and the domain of

MVNO 1 is also referred to herein as a virtual IMS operator domain. Notethat, as used herein, an MVNO “domain” or virtual IMS operator “domain”is a term used to indicate that the respective nodes (e.g., IMS node(s)102 that are in the “domain”) are owned by the respective MVNO orvirtual IMS operator. Likewise, in this example, a second MVNO (MVNO 2)owns one or more IMS nodes 102-2. Again, the IMS nodes 102-2 arereferred to herein as being in a “domain” of MVNO 2. Since we aredealing with the IMS, MVNO 2 is also referred to herein as a virtual IMSoperator, and the domain of MVNO 2 is also referred to herein as avirtual IMS operator domain. Also in this example, a third MVNO (MVNO 3)owns one or more IMS nodes 102-3. Again, the IMS nodes 102-3 arereferred to herein as being in a “domain” of MVNO 3. Since we aredealing with the IMS, MVNO 3 is also referred to herein as a virtual IMSoperator, and the domain of MVNO 3 is also referred to herein as avirtual IMS operator domain.

The MVNOs (MVNO 1, MVNO 2, and MVNO 3) have agreements with an IMSservice provider by which they lease (or otherwise have access to) IMSservice(s) provided by IMS nodes owned by the IMS service provider. Thisleasing is preferably pay-per-use. The IMS service provider may be awholesale IMS service provider and may provide IMS services such as,e.g., specific ASs, media resources (e.g., conferencing equipment,announcement equipment), transcoding equipment, etc. The IMS nodes ownedby the IMS service provider are referred to herein as being in an IMSservice provider domain. In this example, the IMS service provider ownsan IMS network, which is referred to herein as being an IMS network ofthe IMS service provider or equivalently an IMS network in the IMSservice provider domain. As illustrated, the IMS nodes in the IMSservice provider domain include an IBCF 104 that serves as an interfacebetween the IMS nodes 102 in the virtual IMS operator domains and theIMS network in the IMS service provider domain. The IMS service providerdomain also includes one or more additional IMS nodes 106 that provideIMS services. These IMS services include IMS services 108 that can beleased by virtual IMS operators. In addition, CDRs 110 are also createdand stored in the IMS service provider domain, e.g., in order to billthe virtual IMS operators for IMS services, e.g., on a per IMS servicebasis, based on the amount of IMS services provided, based on the typesof IMS services provided, and/or the like. Importantly, different IMSleased services are associated with different IMS network slices. Forexample, each IMS service that can be leased can be associated with adifferent IMS network slice. As another example, different sets of IMSleased services can be associated with different IMS network slices. Inother words, there are preferably multiple IMS network slices in the IMSservice provider domain, where each IMS network slice is used to provideone or more IMS leased services. Note that the IMS service that isoffered to the end user should be distinguished from the leased IMSservice offered to the virtual IMS network operator as an integral partof the overall end user service.

In this example, User Equipments (UEs) UE1 and UEx access IMS servicesvia MVNO 1, UE2 and UEy access IMS services via MVNO 2, and UE3 and UEzaccess IMS services via MVNO 3. While not illustrated in FIG. 1, the UEsaccess the IMS nodes (e.g., the IMS nodes 102) via Radio AccessNetwork(s) (RAN(s)) and core network(s) that are, e.g., owned by therespective MVNOs or are accessible to the respective MNVOs via, e.g.,agreements with the owner(s) of the RAN(s) and core network(s). Further,in this example, UE4 and UEh access IMS services via the IMS network ofthe IMS service provider.

FIG. 2 illustrates the operation of an IMS node 102 in one of thevirtual IMS operator domains and the IBCF 104 in the IMS serviceprovider domain in accordance with some embodiments of the presentdisclosure. As illustrated, an IMS node 102 in a particular virtual IMSoperator domain (e.g., in the domain of a particular MVNO) sends a SIPmessage to the IBCF 104 (step 200). The SIP message is also referred toherein as a SIP request such as, e.g., a SIP Session Initiation Request.The SIP message operates as a request for a desired IMS service(s). TheSIP message includes:

-   -   information that identifies an IMS network slice (e.g., an IMS        network slice associated with the requested IMS service); and/or    -   information that identifies the virtual IMS network operator;        and/or    -   information that identifies the requested leased IMS service;        and/or    -   information that identifies one or more sub-services requested        for the requested leased IMS service (e.g., an enumerated list        for sub-services if applicable (e.g., specific language for        announcement, multi-language for conferencing, etc.), where this        list can be per service (e.g., conferencing has its own list,        MMTEL has its own list, etc.)); and/or    -   information that identifies an IMS network slice instance (e.g.,        an instance of an IMS network slice associated with the        requested IMS service).

The requested leased IMS service may be any IMS service that is, e.g.,leased by the IMS service provider. For example, the requested leasedIMS service may be a media related function (e.g., playing anannouncement). As another example, the requested leased IMS service maybe transcoding. As another example, the requested leased IMS service maybe an IMS service related to a conference call.

The IBCF 104 makes a decision as to whether to accept the request forthe leased IMS service or reject the request for the leased IMS servicebased on the information comprised in the SIP message (step 202). Insome embodiments, the IBCF 104 makes this decision by performing one ormore checks. These check(s) include:

-   -   authenticating that the request belongs to the virtual IMS        network operator; and/or    -   ensuring that the virtual IMS network operator is entitled for        the requested leased IMS service (i.e., ensuring that the        virtual IMS network operator is a subscriber to the requested        leased IMS service); and/or    -   validating the IMS network slice and the requested leased IMS        service (e.g., assuming that there are different IMS network        slices for different IMS services that can be leased, validating        that the requested leased IMS service matches the IMS network        slice indicated in the request); and/or    -   validating that a Session Description Protocol (SDP) (which is        included in the SIP initiation request) matches the requested        IMS service.

The IBCF 104 decides to accept the request if the check(s) is successful(e.g., if the requested is successfully authenticated). Otherwise, theIBCF 104 decides to reject the request. If the IBCF 104 decides toaccept the request, the IBCF 104 initiates the requested leased IMSservice using one or more of the IMS nodes 106 in the IMS serviceprovider domain (step 204A). Conversely, if the IBCF 104 decides toreject the request, the IBCF 104 optionally sends a reject message tothe IMS node 102 (step 204B).

Again, while the example of FIG. 2 uses IMS network slice(s) to identifythe requested IMS service(s), as discussed above, the present disclosureis not limited thereto. In some other embodiments, the SIP message instep 200 may include information, other than IMS network sliceinformation, that identifies the requested leased IMS service(s). Thisinformation may include, for example, a predefined identifier associatedwith the requested leased IMS service(s).

FIGS. 3A and 3B illustrate a specific example in which an MVNO owns itsMTAS but leases media announcement services from the IMS serviceprovider (e.g., another IMS operator). The steps in FIGS. 3A and 3B are:

-   -   Step 1: In step 1, a UE attaches to an access network and        establishes a Packet Data Network (PDN) connection to the IMS,        e.g., in the conventional manner.    -   Step 2: In step2, the UE establishes an IMS registration, e.g.,        in the conventional manner based on existing procedures. In this        example, the MVNO includes its own HSS. In other words, the IMS        node(s) 102 of this particular MVNO includes an HSS. In        addition, as illustrated in FIGS. 3A and 3B, the IMS node(s) 102        of this particular MVNO includes a P-CSCF, an S-CSCF, and an        MTAS.    -   Steps 3A-3C: In steps 3A-3B, the UE (now referred to as UEa)        initiates a session towards another UE, referred to as UEb. The        session arrives at the MTAS in step 3C.    -   Step 4: In step 4, the MTAS decides to initiate an announcement        to UEa before delivering the session to UEb.    -   Steps 5-6: In steps 5-6, the MTAS initiates a new session acting        as a Back-to-Back User Agent (B2BUA) towards the announcement        service owned by the IMS service provider with whom the MVNO has        an agreement. Specifically, the MTAS sends an SIP INVITE message        to the S-CSCF, where the SIP INVITE includes:    -   an identifier of the MVNO (or an identifier of the virtual IMS        operator); and/or    -   an IMS network slice identifier that identifies the IMS network        slice (e.g., the IMS network slice associated with the requested        leased IMS service); and/or    -   information that indicates the requested IMS service; and/or    -   an enumerated list for sub-services if applicable (e.g.,        specific language for announcement, multi-language for        conferencing, etc.). This list can be per service, for example        conferencing has its own list, the MMTEL has its own list, etc.;        and/or    -   an identifier of an IMS network slice instance (e.g., an        identifier of a particular instance of the IMS network slice        associated with the requested leased IMS service).

Note that, in some embodiments, there may be a 1-to-1 mapping betweenIMS network slices and leased IMS services such that the informationthat identifies the IMS network slice also identifies the requestedleased IMS service. The S-CSCF sends the SIP INVITE to the IBCF 104.

-   -   Step 7: In step 7, the incoming request to the IMS service        provider arrives at the IBCF 104. The IBCF 104 decides whether        to accept or reject the request. Specifically, the IBCF 104        makes this decision by performing any one or more of the        following checks:    -   The IBCF 104 authenticates the incoming request (e.g.,        determines that the request is actually from the MVNO or virtual        IMS operator). This can be achieved by several means. For        example, the operator identity must correspond to the incoming        trunk Identifier (ID) where the request came from. A Transport        Layer Security (TLS) can be also established between the        operator and the IBCF 104. Other techniques can also be used to        enable such an authentication to be performed.    -   The IBCF 104 ensures that the MVNO or virtual IMS operator is        entitled for the leased service.    -   The IBCF 104 ensures the IMS network slice is valid and that the        requested IMS service is valid, (e.g., conformant to the        agreement between the IMS service provider and the MVNO or        virtual IMS operator).    -   The IBCF 104 validates that the SDP matches the requested leased        service where applicable.    -   Steps 8-12: In steps 8-12, the announcement is played. More        specifically, the IBCF 104 initiates the requested IMS service        (the announcement) by sending an SIP invite to the appropriate        media resource(s) in the IMS service provider domain (step 8),        where the needed media resource(s) is engaged (step 9).    -   Step 13: In step 13, the MTAS stops the announcement.    -   Step 14: In step 14, the MTAS tears down the announcement        session with the IMS service provider.    -   Step 15: In step 15, the IBCF 104 creates one or more        appropriate CDRs to reflect that the IMS service provider        provided the announcement for the MVNO or virtual IMS operator.    -   Step 16: In step 16, the MTAS establishes the session towards        the target UEb, based on existing procedures.

Again, while the example of FIGS. 3A and 3B uses IMS network slice(s) toidentify the requested IMS service(s), as discussed above, the presentdisclosure is not limited thereto. In some other embodiments, the SIPmessage in steps 5, 6, and 8 may include information, other than IMSnetwork slice information, that identifies the requested leased IMSservice(s). This information may include, for example, a predefinedidentifier associated with the requested IMS service(s).

FIG. 4 illustrates another example. This example is about conferencingequipment. No detailed call flow is shown; however, FIG. 4 illustrateshow the framework of FIG. 1 is used. FIG. 4 shows the three casestypically pertinent to a conferencing server, and has all the neededdetails to understand the scenario.

Another example service that may be leased from the IMS service provideris transcoding. For transcoding, the same principles apply. The MTASacts as a third-party call control for the media resources, via the IBCF104, and the terminating side if transcoding is performed in theterminating or originating network. No call flow is shown as the sameprinciples as described above are applied. The distinction is that thenetwork slice identifier and the requested service correspond totranscoding (see Technical Specification (TS) 23.218 annex B forexamples).

In the embodiments described above, an SIP message including IMS networkslice information (or some other type of information that identifies therequested leased IMS service(s)) is sent from the MVNO domain to thedomain of the IMS service provider. FIG. 5 illustrates an alternativeembodiment in which the SIP messages received in the domain of the IMSservice provider from the MVNO domain do not include IMS network sliceinformation or other types of information that identifies the requestedleased IMS service(s). Instead, an AS 500 in the IMS network of the IMSservice provider receives an SIP message from a particular MVNO andenforces a leasing agreement between that MVNO and the IMS serviceprovider. Assuming that the SIP message needs a particular leased IMSservice(s) and that the MVNO has leased the needed IMS service(s), theAS 500 initiates the needed IMS service(s) within the IMS serviceprovider domain using, e.g., SIP message(s) that include IMS networkslice information or other information that identify the IMS service(s)(i.e., the IMS service(s) used by the MVNO in accordance with theleasing agreement with the IMS service provider).

The SIP message from the MVNO domain may be provided to the AS 500 froman IMS node 102 in the MVNO domain (also referred to as a virtual IMSoperator domain in this context), as illustrated in FIG. 6.Alternatively, the SIP message from the MVNO domain may be provided tothe AS 500 from, e.g., a UE that is subscribed to the MVNO and/or theIMS network of the IMS service provider, as illustrated in FIG. 7.

Looking first at FIG. 6, the IMS node 102 in the virtual IMS operatordomain sends an SIP message to the AS 500 in the IMS service providerdomain (step 600). Unlike the SIP message in the embodiment of, e.g.,FIG. 2, the SIP message here does not include IMS network sliceinformation or other information that identifies a requested leased IMSservice(s). Upon receiving the SIP message, the AS 500 enforces what isneeded for the virtual IMS network operator (step 602). Morespecifically, the AS 500 identifies the MVNO (e.g., in any desiredmanner such as, e.g., the Identity of the originating subscriber, or anyother manner). The AS 500 then determines whether any pay-per-use IMSservices are needed. If so, the AS 500 initiates the needed IMSservice(s) using message(s) that include an indication of the IMSservice(s) (e.g., IMS network slice information for the correspondingleased IMS network slice(s) or other type of information that indicatesthe needed IMS service(s)) (step 604).

Conversely, in the embodiment of FIG. 7, the AS 500 in the IMS serviceprovider domain receives an SIP message from the MVNO domain of aparticular MVNO (step 700). This SIP message may be provided by, e.g., aUE that has a subscription to the MVNO. Upon receiving the SIP message,the AS 500 enforces what is needed for the virtual IMS network operator(step 702). More specifically, the AS 500 determines whether any leasedIMS service(s) is needed for processing of the SIP message and, if so,determines whether the virtual IMS operator has access to the needed IMSservice(s) via an appropriate leasing agreement with the IMS serviceprovider. If so, the AS 500 initiates the needed IMS service(s) using amessage(s) that includes an indication of the leased IMS service(s)(e.g., IMS network slice information for the corresponding IMS networkslice(s) or other type of information that indicates the needed IMSservice(s)) (step 704).

FIGS. 8A and 8B illustrate a specific example in which the MVNO does notown the MTAS and the MVNO leases media announcement services from theIMS service provider (e.g., another IMS operator). The steps in FIGS. 8Aand 8B are:

-   -   Step 1: In step 1, a UE attaches to an access network and        establishes a PDN connection to the IMS, e.g., in the        conventional manner.    -   Step 2: In step 2, the UE establishes an IMS registration, e.g.,        in the conventional manner based on existing procedures. In this        example, the MVNO includes its own HSS. In other words, the IMS        node(s) 102 of this particular MVNO includes an HSS. In        addition, as illustrated in FIGS. 8A and 8B, the IMS node(s) 102        of this particular MVNO includes a P-CSCF and an S-CSCF.    -   Steps 3A-3C: In steps 3A-3B, the UE (now referred to as UEa)        initiates a session towards another UE, referred to as UEb. The        session arrives at the MTAS in step 3C.    -   Step 4: In step 4, the MTAS enforces what is needed by the MVNO.        More specifically, the MTAS identifies the MVNO (e.g., in any        desired manner such as, the identity of the originating        subscriber, or any other manner). The MTAS then determines        whether any pay-per-use IMS services are needed. In this        example, an announcement to UEa is needed before delivering the        session to UEb, and the MVNO has an appropriate leasing        agreement with the IMS service provider.    -   Steps 5-8: In steps 5-8, the announcement is played. More        specifically, the MTAS initiates the requested IMS service (the        announcement) by sending an SIP INVITE to the appropriate media        resource(s) in the IMS service provider domain (step 5), where        the needed media resource(s) is engaged (step 6). The SIP INVITE        includes:    -   an identifier of the MVNO (or an identifier of the virtual IMS        operator); and/or    -   an IMS network slice identifier that identifies the IMS network        slice (e.g., the IMS network slice associated with the requested        leased IMS service); and/or    -   information that indicates the requested IMS service; and/or    -   an enumerated list for sub-services if applicable (e.g.,        specific language for announcement, multi-language for        conferencing, etc.). This list can be per service, for example        conferencing has its own list, MMTEL has its own list, etc.;        and/or    -   an identifier of an IMS network slice instance (e.g., an        identifier of a particular instance of the IMS network slice        associated with the requested leased IMS service).    -   Note that, in some embodiments, there may be a 1-to -1 mapping        between IMS network slices and leased IMS services such that the        information that identifies the IMS network slice also        identifies the requested leased IMS service. The S-CSCF sends        the SIP INVITE to the IBCF 104.    -   Step 9: In step 9, the MTAS stops the announcement.    -   Step 10: In step 10, the MTAS tears down the announcement.    -   Step 11: In step 11, the MTAS creates one or more appropriate        CDRs to reflect that the IMS service provider provided the        announcement for the MVNO.    -   Step 12: In step 12, the MTAS establishes the session towards        the target UEb, based on existing procedures.

Network slicing utilizes virtualization technology (e.g., SoftwareDefined Networking (SDN) and Network Function Virtualization (NFV)) toallow multiple virtual (i.e., logical) networks to be created on top ofa common shared physical infrastructure. These virtual networks arereferred to as network slices. The network slices can then be customizedto meet needs of different use cases. In this regard, the IMS of the IMSservice provider implemented in the IMS service provider domain includesmultiple IMS network slices that are implemented on the same physicalinfrastructure. In this regard, while not illustrated in FIG. 1, the IMSservice provider domain includes a number of IMS physical infrastructurenodes.

FIG. 9 is a schematic block diagram of an IMS physical infrastructurenode 900. The IMS network slices are logical or virtual networks thatare implemented using virtualization technology on a number of IMSphysical infrastructure nodes such as the IMS physical infrastructurenode 900. In this regard, the IMS nodes 106 in the IMS service providerdomain may be implemented as virtual nodes operating one or more IMSphysical infrastructure nodes 900. Note, however, that some of the IMSnodes 106 may alternatively be implemented as physical nodes (i.e., asphysical infrastructure nodes). Likewise, the IBCF 104 may beimplemented as a physical infrastructure node 900 or implemented as avirtual node that operates on one or more physical infrastructure nodes900. In the same manner, the IMS nodes 102 may be virtual nodesoperating on IMS physical infrastructure nodes or IMS physicalinfrastructure nodes 900.

In this regard, as illustrated in FIG. 9, the IMS physicalinfrastructure node 900 includes one or more processors 902 (e.g.,Central Processing Units (CPUs), Application Specific IntegratedCircuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or thelike), memory 904, and a network interface(s) 906. In some embodiments,using virtualization, the IMS nodes 102 or 106 and/or the IBCF 104 areimplemented as virtual nodes that utilize physical resources (e.g., theprocessor(s) 902, the memory 904, and the network interface(s) 906) ofIMS physical infrastructure nodes 900.

In some embodiments, a computer program including instructions which,when executed by at least one processor, causes the at least oneprocessor to carry out the functionality of an IMS node according to anyof the embodiments described herein is provided. In some embodiments, acarrier comprising the aforementioned computer program product isprovided. The carrier is one of an electronic signal, an optical signal,a radio signal, or a computer readable storage medium (e.g., anon-transitory computer readable medium such as memory).

FIG. 10 is a schematic block diagram of the IMS physical infrastructurenode 900 according to some other embodiments of the present disclosure.The IMS physical infrastructure node 900 includes one or more modules1000, each of which is implemented in software. The module(s) 1000provide the functionality of one or more of the IMS nodes describedherein.

Any appropriate steps, methods, features, functions, or benefitsdisclosed herein may be performed through one or more functional unitsor modules of one or more virtual apparatuses. Each virtual apparatusmay comprise a number of these functional units. These functional unitsmay be implemented via processing circuitry, which may include one ormore microprocessor or microcontrollers, as well as other digitalhardware, which may include Digital Signal Processor (DSPs),special-purpose digital logic, and the like. The processing circuitrymay be configured to execute program code stored in memory, which mayinclude one or several types of memory such as Read Only Memory (ROM),Random Access Memory (RAM), cache memory, flash memory devices, opticalstorage devices, etc. Program code stored in memory includes programinstructions for executing one or more telecommunications and/or datacommunications protocols as well as instructions for carrying out one ormore of the techniques described herein. In some implementations, theprocessing circuitry may be used to cause the respective functional unitto perform corresponding functions according one or more embodiments ofthe present disclosure.

While processes in the figures may show a particular order of operationsperformed by certain embodiments of the present disclosure, it should beunderstood that such order is exemplary (e.g., alternative embodimentsmay perform the operations in a different order, combine certainoperations, overlap certain operations, etc.).

Some example embodiments of the present disclosure are as follows:

Embodiment 1: A method performed by an Interconnect Border ControlFunction, IBCF, in an Internet Protocol, IP, Multimedia Subsystem, IMS,network of an IMS service provider to provide IMS services to a virtualIMS network operator, comprising:

-   -   receiving, from an IMS node in a virtual IMS network domain of a        virtual IMS network operator, a Session Initiation Protocol,        SIP, message that serves as a request for a leased IMS service,        the SIP message comprising:        -   information that identifies the leased IMS service; and/or        -   information that identifies an IMS network slice (e.g., an            IMS network slice associated with the leased IMS service);            and/or        -   information that identifies the virtual IMS network            operator; and/or        -   information that identifies one or more sub-services            requested for the leased IMS service; and/or        -   information that identifies an IMS network slice instance            (e.g., an instance of an IMS network slice associated with            the leased IMS service); and    -   making a decision as to whether to accept the request for the        leased IMS service or reject the request for the leased IMS        service based on the information comprised in the SIP message.

Embodiment 2: The method of embodiment 1 wherein: the decision is toaccept the request for the leased IMS service; and the method furthercomprises, upon making the decision to accept the request for the leasedIMS service, initiating the requested IMS service using one or more IMSnodes in the IMS network.

Embodiment 3: The method of embodiment 2 further comprising creating oneor more charging data records that reflect that the requested leased IMSservice was provided for the virtual IMS network operator.

Embodiment 4: The method of embodiment 1 wherein: the decision is toreject the request for the leased IMS service; and the method furthercomprises, upon making the decision to reject the request for the leasedIMS service, sending a message to the IMS node in the virtual IMSnetwork domain that indicates that the request for the requested leasedIMS service is rejected.

Embodiment 5: The method of any one of embodiments 1 to 4 wherein makingthe decision as to whether to accept the request for the leased IMSservice or reject the request for the leased IMS service comprises:

-   -   authenticating that the request belongs to the virtual IMS        network operator; and/or    -   ensuring that the virtual IMS network operator is entitled for        the leased IMS service; and/or    -   validating the IMS network slice and the leased IMS service        (e.g., validating that the leased IMS service is one that is        leased by the virtual IMS network operator); and/or    -   validating that a Session Description Protocol, SDP, matches the        requested IMS service.

Embodiment 6: The method of any one of embodiments 1 to 5 furthercomprising providing at least a portion of the information comprised theSIP message to another IMS node in the IMS network of the IMS serviceprovider.

Embodiment 7: The method of any one of embodiments 1 to 6 wherein theleased IMS service is a media related function (e.g., playing anannouncement).

Embodiment 8: The method of any one of embodiments 1 to 6 wherein theleased IMS service is transcoding.

Embodiment 9: The method of any one of embodiments 1 to 6 wherein theleased IMS service is an IMS service related to a conference call.

Embodiment 10: An Interconnect Border Control Function, IBCF, for anInternet Protocol, IP, Multimedia Subsystem, IMS, network for providingIMS services to a virtual IMS network operator, the IBCF adapted toperform the method of any one of embodiments 1 to 9.

Embodiment 11: An Interconnect Border Control Function, IBCF, for anInternet Protocol, IP, Multimedia Subsystem, IMS, network for providingleased IMS services to a virtual IMS network operator, the IBCFcomprising an interface and processing circuitry that causes the IBCF toperform the method of any one of embodiments 1 to 9.

Embodiment 12: A method performed by an Internet Protocol, IP,Multimedia Subsystem, IMS, node in a virtual IMS network domain of avirtual IMS network operator to request a leased IMS service from an IMSnetwork, comprising:

-   -   sending, to an Interconnect Border Control Function, IBCF, in        the IMS network, a Session Initiation Protocol, SIP, message        that serves as a request for a leased IMS service, the SIP        message comprising:        -   information that identifies the leased IMS service; and/or        -   information that identifies an IMS network slice (e.g., an            IMS network slice associated with the leased IMS service);            and/or        -   information that identifies the virtual IMS network            operator; and/or        -   information that identifies one or more sub-services            requested for the leased IMS service; and/or        -   information that identifies an IMS network slice instance            (e.g., an instance of an IMS network slice associated with            the leased IMS service).

Embodiment 13: The method of embodiment 12 wherein the leased IMSservice is a media related function (e.g., playing an announcement).

Embodiment 14: The method of embodiment 12 wherein the leased IMSservice is transcoding.

Embodiment 15: The method of embodiment 12 wherein the leased IMSservice is an IMS service related to a conference call.

Embodiment 16: An Internet Protocol, IP, Multimedia Subsystem, IMS, nodein a virtual IMS network domain of a virtual IMS network operator torequest a leased MS service from an IMS network, the IMS node adapted toperform the method of any one of embodiments 12 to 15.

Embodiment 17: An Internet Protocol, IP, Multimedia Subsystem, IMS, nodein a virtual IMS network domain of a virtual IMS network operator torequest a leased IMS service from an IMS network, the IMS nodecomprising an interface and processing circuitry that causes the IMSnode to perform the method of any one of embodiments 12 to 15.

Embodiment 18: A method performed by an Application Server, AS, in anInternet Protocol, IP, Multimedia Subsystem, IMS, network of an IMSservice provider to provide leased IMS services to a virtual networkoperator, comprising:

-   -   receiving, from a virtual network operator domain of the virtual        network operator, a Session Initiation Protocol, SIP, message;    -   upon receiving the SIP message, determining that a leased IMS        service is needed to process the SIP message; and    -   initiating the leased IMS service in the IMS network of the IMS        service provider by sending a second SIP message to another node        in the IMS network of the IMS service provider, the second SIP        message comprising:        -   information that identifies the leased IMS service; and/or        -   information that identifies an IMS network slice (e.g., an            IMS network slice associated with the leased IMS service);            and/or        -   information that identifies the virtual network operator;            and/or        -   information that identifies one or more sub-services desired            for the leased IMS service; and/or        -   information that identifies an IMS network slice instance            (e.g., an instance of an IMS network slice associated with            the leased IMS service).

Embodiment 19: The method of embodiment 18 wherein one or more chargingdata records are created that reflect that the leased IMS service wasprovided for the virtual network operator (e.g., based on theinformation comprised in the second SIP message).

Embodiment 20: The method of embodiment 18 or 19 wherein the leased IMSservice is a media related function (e.g., playing an announcement).

Embodiment 21: The method of embodiment 18 or 19 wherein the leased IMSservice is transcoding.

Embodiment 22: The method of embodiment 18 or 19 wherein the leased IMSservice is an IMS service related to a conference call.

Embodiment 23: An Application Server, AS, in an Internet Protocol, IP,Multimedia Subsystem, IMS, network of an IMS service provider, the ASadapted to perform the method of any one of embodiments 18 to 22.

Embodiment 24: An Application Server, AS, in an Internet Protocol, IP,Multimedia Subsystem, IMS, network of an IMS service provider, the AScomprising an interface and processing circuitry that causes the AS toperform the method of any one of embodiments 18 to 22.

At least some of the following abbreviations may be used in thisdisclosure. If there is an inconsistency between abbreviations,preference should be given to how it is used above. If listed multipletimes below, the first listing should be preferred over any subsequentlisting(s).

AS Application Server

ASIC Application Specific Integrated Circuit

B2BUA Back-to-Back User Agent

CDR Charging Data Record

CPU Central Processing Unit

DSP Digital Signal Processor

FPGA Field Programmable Gate Array

HSS Home Subscriber Server

IBCF Interconnect Border Control Function

ID Identifier

IMS Internet Protocol Multimedia Subsystem

IP Internet Protocol

MMTEL Multimedia Telephony

MTAS Multimedia Telephony Application Server

MVNO Mobile Virtual Network Operator

NFV Network Function Virtualization

P-CSCF Proxy Call Session Control Function

PDN Packet Data Network

RAM Random Access Memory

RAN Radio Access Network

ROM Read Only Memory

S-CSCF Serving Call Session Control Function

SDN Software Defined Networking

SDP Session Description Protocol

SIP Session Initiation Protocol

TLS Transport Layer Security

TS Technical Specification

UE User Equipment

VoLTE Voice over Long Term Evolution

Those skilled in the art will recognize improvements and modificationsto the embodiments of the present disclosure. All such improvements andmodifications are considered within the scope of the concepts disclosedherein.

1. A method performed by an Interconnect Border Control Function, IBCF,in an Internet Protocol, IP, Multimedia Subsystem, IMS, network of anIMS service provider to provide IMS services to a virtual IMS networkoperator, comprising: receiving, from an IMS node in a virtual IMSnetwork domain of a virtual IMS network operator, a Session InitiationProtocol, SIP, message that serves as a request for a leased IMSservice, the SIP message comprising: a. information that identifies theleased IMS service; b. information that identifies an IMS network slice;c. information that identifies the virtual IMS network operator; d.information that identifies one or more sub-services requested for theleased IMS service; e. information that identifies an IMS network sliceinstance; or f. any combination of two or more of a, b, c, d, and e; andmaking a decision as to whether to accept the request for the leased IMSservice or reject the request for the leased IMS service based on theinformation comprised in the SIP message.
 2. The method of claim 1wherein the SIP message comprises information that identifies an IMSnetwork slice, the IMS network slice being associated with the leasedIMS service.
 3. The method of claim 1 wherein the SIP message comprisesinformation that identifies an IMS network slice instance, the IMSnetwork slice instance being an instance of an IMS network sliceassociated with the leased IMS service.
 4. The method of claim 1wherein: the decision is to accept the request for the leased IMSservice; and the method further comprises, upon making the decision toaccept the request for the leased IMS service, initiating the requestedIMS service using one or more IMS nodes in the IMS network.
 5. Themethod of claim 4 further comprising creating one or more charging datarecords that reflect that the requested leased IMS service was providedfor the virtual IMS network operator.
 6. The method of claim 1 wherein:the decision is to reject the request for the leased IMS service; andthe method further comprises, upon making the decision to reject therequest for the leased IMS service, sending a message to the IMS node inthe virtual IMS network domain that indicates that the request for therequested leased IMS service is rejected.
 7. The method of claim 1wherein making the decision as to whether to accept the request for theleased IMS service or reject the request for the leased IMS servicecomprises: i. authenticating that the request belongs to the virtual IMSnetwork operator; ii. ensuring that the virtual IMS network operator isentitled to the leased IMS service; iii. validating the IMS networkslice and the leased IMS service; iv. validating that a SessionDescription Protocol, SDP, matches the requested IMS service; or v. anycombination of two or more of i, ii, iii, and iv.
 8. The method of claim1 further comprising providing at least a portion of the informationcomprised the SIP message to another IMS node in the IMS network of theIMS service provider.
 9. The method of claim 1 wherein the leased IMSservice is a media related function.
 10. The method of claim 1 whereinthe leased IMS service is making an announcement.
 11. The method ofclaim 1 wherein the leased IMS service is transcoding.
 12. The method ofclaim 1 wherein the leased IMS service is an IMS service related to aconference call. 13-16. (canceled)
 17. A method performed by an InternetProtocol, IP, Multimedia Subsystem, IMS, node in a virtual IMS networkdomain of a virtual IMS network operator to request a leased IMS servicefrom an IMS network, on behalf of a User Equipment, UE, the methodcomprising: sending, to an Interconnect Border Control Function, IBCF,in the IMS network, a Session Initiation Protocol, SIP, message thatserves as a request for a leased IMS service, the SIP messagecomprising: a. information that identifies the leased IMS service; b.information that identifies an IMS network slice; c. information thatidentifies the virtual IMS network operator; d. information thatidentifies one or more sub-services requested for the leased IMSservice; e. information that identifies an IMS network slice instance;or f. any combination of two or more of a, b, c, d, and e.
 18. Themethod of claim 17 wherein the leased IMS service is a media relatedfunction.
 19. The method of claim 17 wherein the leased IMS service istranscoding.
 20. The method of claim 17 wherein the leased IMS serviceis making an announcement.
 21. The method of claim 17 wherein the leasedIMS service is an IMS service related to a conference call. 22-25.(canceled)
 26. A method performed by an Application Server, AS, in anInternet Protocol, IP, Multimedia Subsystem, IMS, network of an IMSservice provider to provide leased IMS services to a virtual networkoperator, comprising: receiving, from a virtual network operator domainof the virtual network operator, a Session Initiation Protocol, SIP,message; upon receiving the SIP message, determining that a leased IMSservice is needed to process the SIP message; and initiating the leasedIMS service in the IMS network of the IMS service provider by sending asecond SIP message to another node in the IMS network of the IMS serviceprovider, the second SIP message comprising: a. information thatidentifies the leased IMS service; b. information that identifies an IMSnetwork slice; c. information that identifies the virtual networkoperator; d. information that identifies one or more sub-servicesdesired for the leased IMS service; e. information that identifies anIMS network slice instance; or f. any combination of two or more of a,b, c, d, and e.
 27. The method of claim 26 wherein one or more chargingdata records are created that reflect that the leased IMS service wasprovided for the virtual network operator.
 28. The method of claim 26wherein the leased IMS service is a media related function. 29-35.(canceled)